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General Information => Troubleshooting => Topic started by: tkisling on June 07, 2010, 08:52:22 pm
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Hi there again. :) I was wondering whether anyone could post a diagram of the drum brake assembly on a 1981 Rabbit diesel L. I'm having a heck of a time figuring out how everything goes together.
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I just did a full makeover on my 81 rear brakes, and took pics.
Should be easy to see details since everything is new/clean.
PM me your email address and i can email a couple/few pix.
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Your profile has email addy, i'll send some pix to that.
I can't post pix to forum because my ISP doesn't cooperate with pic webhost sites. But you can post them here when you get them, if you are able.
The Germans have their own way on drum brakes, first time is a true learning curve. Golden Rule is to leave one side assembled so you can use it as reference on the other side = until you are veteran-ized.
#1 ordeal is that most aftermarket shoes pay no attention to detail on the bend on the emergency brake arm. I had to check 3 different brands/offerings before finding shoes with right bend on e-brake arm. AdvanceAuto and Oreilly failed. AutoZone was right, and so was Carquest.
The stuff will not go together right AND function right - if that bend doesn't allow the shoe/eBrake arm/crossbar to all fit with right clearance in right areas.
Make note that AdvanceAuto has New 180mm Drums for $8 each, if you need them. But i needed 200mm (truck).
Shoes were $14 at AutoZone ($25 Carquest)
Wheel cylinders (Wagner) $10 each Carquest
Spring kit was $4 or $7 at AutoZone
O'Reilly turns drums for $10 each
National bearings and seals $30 for all at AdvanceAuto
The spring colors of my parts may not match your colors, but use my color references in conjunction with my pictures, compared to your physical spring shapes.
Step #1 is to position the notched tabs/ears of the wheel cylinder pistons so that they are to the outside of the vehicle. This keeps the shoes from trying to walk out towards the outer edge of the drum.
Step #2 is to loosen your e-Brake cables to the full limit of the threads, this will make getting the spring end of the cable back onto the e-brake arm of the shoe 500 times easier. At the spring end - pull out the cable slack you created. The cable end will now have freedom from the spring and slip right into place on the eBrake arm of the shoe.
Step #2 is to take the shoe with the eBrake lever, and attach the cable properly to the lever. Do not attach the shoe to the backing plate - leave it free.
Step #3 is to position the crossbar properly over the eBrake lever, and onto the shoe. Then attach the Blue spring to the crossbar, and to the shoe. Let that shoe and crossbar hang together free for now.
Step #4 is to attach the Yellow spring to the other shoe, then position that shoe into the crossbar, and attach other end of yellow spring into crossbar.
Step #5 is to position your shoes/crossbar assembly onto the backing plate. Start by compressing the wheel cylinder pistons in - and manuever the upper section of shoes into position on the wheel cylinder.
Then spread shoe/crossbar assembly apart by hand at lower extremities, and set the lower ends of shoes against the lower stop.
Then attach the hold-down pin/spring/cup to each shoe.
Step #5 attach lower Green spring.
Step #6 with a medium flat blade screwdriver inserted into the crossbar slot where the Blue spring attaches - pry the screwdriver against the brake shoe and open some room to slide the funny little self adjuster tab into place.
Make sure the little 'knob' sticking out on the backside of the self adjuster tab - is facing towards the backing plate - NOT facing towards you. This 'knob' keeps the tab from falling through the crossbar later into the lifespan of the brake shoes.
Position the self adjusting tab so that the top of it is about even with the top of the brake shoe.
Attach Purple spring to bottom of self adjuster, and into brake shoe.
Double check that you still have the brake cylinder piston "ears" facing towards outside of vehicle.
If you aren't positive about the operation of old wheel cylinders, have someone mash the brake pedal now while you watch for their action moving and releasing the shoes.
Center the shoes/assembly up on the backing plate by eye to the best of your visual perception. So that the drum will hopefully just plop right back on without interference.
Tighten wheel bearing nut with a wrench just beyond hand tight enough to set everything into place. Then loosen the nut back, and hand tighten. Go just a tiny bit past hand tight with a wrench.
Be sure to use a new cotter pin.
Drive car and do full stops in forward and reverse.
About 10-15+ times in forward and reverse.
Jack vehicle back up, and verify that wheels still turn freely.
Hearing "some very slight" brake rubbing is usually normal and will wear in quickly. So long as wheel turns pretty freely.
If all that checks out proper, now you can adjust your emergency brake and fine tune it to your liking. Engage and disengage the eBrake numerous times after adjustments and check for equal amount of grab on both wheels at certain numbers of clicks.
Adjust as necessary.
Standard setting is 4-5 clicks up on handle and you shouldn't be able to turn wheels any by hand. But that can be to your own taste, tighter or looser.
After final eBrake tuning, re-check that wheels still turn freely with eBrake disengaged. And you're done with it.
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Thanks so much for the info. This is really going to help since I don't have a bentley manual. I bought the Wagner brand shoes, wheel cylinder, and spring/hardware kit from Oreilly's so I hope this all works. <:/
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If you went with Wagner shoes instead of their house brand, you should be in great shape.
You can tell ahead of time by fitting the crossbar into shoe that has the eBrake lever on it. If it all fits in the crossbar flush, and has clearance for the eBrake lever travel - you're good to go.
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Hi, I was wondering if this self adjuster lever fits into a groove or something or if it just gets wedged into the backing plate by the shoe. It seems like it has no particular place to sit and would just fall off if I just wedged it in there.
heres some photos:
http://img16.imageshack.us/i/img0897oc.jpg/ (http://img16.imageshack.us/i/img0897oc.jpg/)
http://img195.imageshack.us/i/img0895g.jpg/ (http://img195.imageshack.us/i/img0895g.jpg/)
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Did you get the pix i emailed to you ?
I can't view your pix, imageshack refuses to jive with my ISP in any form. But you can send them to my email.
Read back through step #6 another time or so, and check the pix i sent. Might help sort it out.
The goofy lil adjuster fits in a "slot" in the crossbar, it wedges between the brake shoe and crossbar. Its an odd design, but simple. And evidently works about 95% of the time.
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I did receive your pics just fine. By the "slot" do you mean the angled, open section of the crossbar the long blue spring passes through?
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No, the slot for the blue spring is on Outer side of the brake shoe.
The slot for the eBrake adjuster wedge is on Inner side - behind the brake shoe. It slips in right behind the upper metal part of the brake shoe.
Take note again of inserting a flat screwdriver into the small slot where the blue spring actually attaches - then leverage the screwdriver against the brake shoe applying mild force to open the gap for the adjuster to slip into - on backside of the brake shoe.
If you can:
download the pix i sent - to your computer - then open them with your picture viewing software - then enlarge/explode the view of picture numbers DSC02099 and DSC02102.
Those pics show the adjuster location pretty good - considering most of the adjuster is hidden. That should help you tremendously if you can enlarge those pics.
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I would use caution if you have someone "just mash the brake petal" to see if the wheel cylinders are working. Flooring the brake petal without the drums on is usually a great way to push the plunger out of the cylinder, drenching everything with brake fluid and usually necessitating replacing the wheel cylinders and shoes. ask me how I know this.
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Well, me and my dad finally got both rear drum brake shoes and new wheel cylinders installed, it wasn't easy, but we got er' done in the end. Now I am faced with the original problem before I started all this, my system has no pressure. I am assuming I need to bleed the brakes. But I do not know the specific process of brake bleeding a system with two new cylinders. Can anyone help me finish this saga?
ps. Big thanks to "Baron VonZeppelin" for all his advice and the complete instructions, it really helped.
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Here's a very good write-up http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/reardrum/index.htm (http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/reardrum/index.htm)
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Good stuff there!
While you are at this job, or any job involving bleeding brakes, make yourself one of these...
http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/bleeder/index.htm (http://faculty.ccp.edu/faculty/dreed/Campingart/jettatech/bleeder/index.htm)
I must have saved myself days of work (and a marriage) using one...
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I am assuming I need to bleed the brakes
Yep, probably 100 diffy ways to do it.
If you don't want to make or buy a device, there are other ways.
What you will likely find - since you had bad cylinder(s) already - is that the lines leading up to them will have rusty'ish brake fluid and some corrosion from the air and moisture that was drawn back into them over time. You need to get that mess out.
I would NOT want to pump that garbage through my new cylinders to get it out of the system. I would disconnect the lines from the cylinders (both) before pumping/bleeding the lines - which would send the garbage through the cylinder(s) otherwise. If you only disconnect one at a time - the other will be getting the stuff run into it.
So i would disconnect both and do an initial Flush of both lines.
I used a MightyVac hand pump vacuum tool on mine to flush them until clear fluid was coming out each line - before connecting the lines to the new cylinders. And then pressure bled them.
Another method would be to run lengths of (old/new) vacuum or fuel hose or clear vinyl tubing from each brake line (something that fits tightly over the line nipple - not the line nut). Enough hose so that both hoses can meet near the middle of the car. Clear vinyl tubing is ideal - but not required.
Have a catch pan/jar/jug to catch what comes out.
Have a helper to work the brake pedal in car, and he will also refill the brake fluid reservoir as needed.
Wear some type of rubber/vinyl/latex gloves - hold both hoses into catch container.
Have helper push down brake pedal with medium pressure to the bottom. He holds it there. Then you cover the hoses with a gloved finger - and tell him - OKAY. He lets the pedal up - and says OKAY back at you when its back up completely.
You let your fingers off the hoses and tell him - OKAY. He pushes pedal down again to the bottom and says OKAY. You put fingers over hoses and tell him - OKAY, and keep repeating that process until you get clean fluid coming out both sides. It takes good teamwork and communication - and you can use more words than just okay.
You want the hoses to be covered anytime the brake pedal is going up - so that you hopefully don't draw air back into the lines. Its not the end if you do slip a couple few times - you're just flushing for now. About every 3-4 flush pumps - check/refill brake fluid level.
This was a guidline. You can do something like this many different ways and you can modify anybodys instructions to fit your needs.
You "might" be able to pump the brake pedal some with your finger over it in the very beginning - but as it gets fluid built up and pressure increasing - i doubt you will be able to do more than one pedal push at a time.
After all that is completed to satisfaction - you can re-connect the brake lines to the wheel cylinders and start the pressure bleed operation. It is pretty similar to the flush operation. Takes teamwork and voice commands.
With the brake lines securely fastened into the wheel cylinders - and the bleeder screws on backside of wheel cylinders run in snug on both sides - put a box end wrench (7mm-8mm) on passenger side bleeder screw and then connect one of your flush hoses over the bleeder screw nipple. Run hose into a container.
Have helper pump brake pedal smoothly about 10 times.
He holds pedal down and gives voice command - you loosen the bleeder screw about a half turn while he pushes pedal to floor and holds.
He gives voice command - you tighten bleeder screw.
Then you give voice command and he lets pedal up.
Then he pumps pedal again .... continue doing this until you get full fluid - no air - coming out of the hose.
Then tighten the bleeder screw snugly.
Remember to keep an eye on brake fluid level every few bleeds, the rear capacity is less than the front and it runs out quickly.
Then do driver side rear.
Then do passenger front.
Then do driver front.
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I have all the tools to bleed the brakes now. But whenever I go to bleed the brakes i can't get any pressure to build up in the system before I loosen the bleeder screw and it appears that the master cylinder level is constant. Do you think my problem is the MC?
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I should also note that NO fluid is coming out on either side on the rear.
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You'll have to go into troubleshoot mode now.
What special tools do you have now to bleed the brakes ?
I'm supposing you don't have a MightyVac pump.
It could be your master cylinder, it could be something else entirely like clogged lines or sediment in the reservoir blocking the rear outlet, it could be multiple issues combined.
I haven't worked on a Rabbit since 1983, and it was a 75 model. So i'm not familiar with exactly how they are set up on the lines.
My 81 truck has 4 independent brake lines from the master cylinder that go to each wheel independently. I don't know if your car is like that or not.
Were both of the wheel cylinders bad/stuck/frozen ?
The longer one is left bad, the more damage/corrosion it does inside the brake line.
Without being there, all i can do is offer suggestions.
Is the lower rear portion of the brake reservoir clear, or is it dirty full of sediment on the bottom ?
If its sedimented pretty bad - you'll need to remove it to clean it out. But don't do that just yet.
And if/when you do - it is usually a very very delicate operation.
They can break easy, especially the nipple outlets that go into master cylinder body. It needs some special prep and proceedure to try to remove it without damage.
If you have a MightyVac, attach it to a rear brake line and trigger it up to about 30-35. If nothing comes out or nothing breaks free - you either have a very bad line or reservoir is completely blocked by sediment.
There are different ways i would approach it from here, depending on whether or not the reservoir is nice and clean looking on the bottom - or whether it looks like it needs to come off and be cleaned out.
Either way - clean or dirty - First i would get most the fluid back out of it as possible. Wick it out with a rag, or whatever works for you.
IF it is nice and clean - can you get the rear brake lines broken loose from the master cylinder ? If so, remove them and then pump brake pedal (covering ports with rag). If you get pressurized fluid - the master is probly good.
You can blow compressed air (about 10-15-20 psi) from the master cylinder lines to the rears - but remove the lines from the wheel cylinders First.
Those results should point you to next repairs needed.
IF the master lines are too difficult and don't want to come loose within reasonable effort. Then do it this way.
Loosely stuff a rag in the top of reservoir instead of putting cap back on.
Then blow low pressure compressed air (maybe 10-15 pounds) into the brake lines from back where the lines go into the wheel cylinders. Be careful moving the hard brake lines above the backing plate - to have clearance to operate.
Have your helper watch reservoir to see what kind of action goes on at reservoir. Hopefully some crap and some nasty fluid will blow back up inside. Try that on both lines.
If that works and both rear lines free up, then you'll probably need to remove the reservoir and clean it out real good afterwards. Then reinstall and Flush the lines Very Good. Then bleed.
Troubleshooting just takes some time and thought.
You want to do whatever you can to verify what is working and what is broken. These cars are old and most have been mistreated neglected or left sitting for extended periods.
If you can't get the lines to flow using above tactics, start removing them one piece at a time at any and every joint connection and find which pieces will flow and which won't.
Good Luck on it being an easy fix.
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Thanks, I'll try and work on it this week.
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Well, I think my culprit is a bad MC. When I push the brake pedal in I can hear a wooshing sound coming from the engine compartment. Also I see a big wet spot behind the MC mounting area on the brake booster. I think that may be brake fluid from the MC failing. I figured out my temp gauge not working was due to one of the three wires for the temp sensor was disconnected.
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Yeh, sounds like classic symptoms of bad master cylinder.
Were the front brakes working ? I was assuming they probably were.
While the lines are apart from master, perfect opportunity to blow them out - then do some fluid flushes through them. I'd do them all, front and rear.
Probly take better part of a quart of brake fluid to flush and bleed them all.
You need special flare nut wrench to get the best contact on the line nuts. An open end wrench will usually just round off the corners. And some are so corroded - nothing will grab them - except strong vise grips. Sometimes the nuts need to be heated with a propane torch. Spraying them ahead of time - several times - with penetrating fluid like PB Blaster is always good.
I would try to get reservoir out of way first, before getting too wild with the brake lines. Maybe you get lucky and yours roll right out, but usually its a battle with old line nuts at the master.
You have to swap your old reservoir to a new master.
Unless you find a pricey alternate that includes a reservoir.
The Parts Place . com sells used reservoirs if you get in trouble.
The reservoir has two plastic flared nipples that go into the master - through rubber grommets. Pull up on reservoir just a bit to a comfortable point - and lubricate the grommets around the nipples. Work reservoir up and down gently to work the lube in.
Do that several times for a day or two ahead.
Get as much of the fluid out as you can before trying to take it off.
To get it off - you have to pull it STRAIT up from master.
Its risky business - but has to be done.
Take your time and work with it.
Best to do it while master is still secured on car.
If you pull up with uneven force - or one nipple comes out first - it will likely break the other nipple off, or crack it at minimum.
The first one i did - the front nipple pulled out first - the overload force and subsequent tilting caused the rear nipple to bend and crack - but it came out. It happened so fast - no time to react.
I was holding a damaged product in the blink of an eye.
I rushed it, and paid the price.
Learned a little though.
Have done numerous since without damage.
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I picked up a new MC today and am going to install it. The manual says to bench bleed it before I install it to the car. But since I don't have access to a vice at the moment, I am thinking of bleeding it once I get it installed. I saw in a tutorial that said if the MC is mounted horizontally without an angle I can skip the bench bleed. Does this sound like a good idea?
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You can "bench-bleed" it on the car - after its bolted up - before lines get connected.
Or if you flush your lines out good with brake fluid using the brake pedal/master cylinder - that will bleed it plenty too.
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Well, I got it in the car but the MC reservoir leaks at the grommets where it mats with the MC. I tried cleaning the surfaces but it didn't help. After pulling it out several times one of the necks on the reservoir cracked. :( Now I gotta try and get a new one.
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On a positive note, the system seems to be working because when I turn the bleeder screws at the wheels, fluid comes out.
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Sorry to hear about the reservoir .... it can happen to anyone.
www.partsplaceinc.com (http://www.partsplaceinc.com) sells good used ones for $15-20.
They specialize in these cars, and will have about anything you might need for your Rabbit - that you can't find locally.
They have every piece for Rabbits like yours, basically.
They parted out a bunch of them.
Ask for their free catalog if you contact them.
In Auburn Hills, Michigan (248) 373-2300
They could get you one to Wisc. pretty quickly.
Last i checked - new reservoirs were $100+ :o
Couldn't find new aftermarket ones anywhere.
Someone needs to make these.
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Well, I was able to hot glue the cracked end of the neck on the reservoir and transferred the grommets from the old MC to the new one. Seems to be working just fine, no leaks, for now. But I still have my same problem, the humming/low wheezing noise coming from the MC/brake booster area. I'll try and bleed air out of the system tomorrow.
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The car is now back together again. The drivers side drum did not turn easily at first. But after driving it turns easier now. But that side gets really hot sand smokes. Should I just let the shoes wear in on that side or should I take it apart again so that it turns a freely as the passenger side and doesn't smoke.
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The drivers side drum did not turn easily at first. But after driving it turns easier now. But that side gets really hot and smokes
Bad signs.
Shouldn't have left the driveway until both sides verified as easy to spin without wheels mounted - after cycling brakes numerous times to verify.
Both drums need to be equally easy to turn by hand (without a wheel mounted).
By easy - they should spin on their own when you give them a brisk roll by hand. Having a wheel mounted can give false reports because of the extra momentive force from the weight of the wheel.
That much heat can disolve the bearing grease pretty quick - and then wheel bearing goes bad, along with other things, like the rubbers in your new wheel cylinders melting, etc... 15 to 20 minutes steady driving is about all it takes.
With good luck, none of that has happened.
The auto-adjuster wedge must be too far down.
Need to pull it back upwards so that the top of the wedge is about even with the top of the shoe.
Then mount drum, check for rolling resistance.
Then work brake pedal about 10 times, check for rolling resistance again after the brakes have cycled some.
If thats checking out - then you can mount wheel and test drive again. Bring it back home and pull wheel to re-check resistance by hand. If all is still well - should be good to go. And can move on to adjusting eBrake cables.
Be careful about grabbing ahold of a potentially hot or super hot brake drum. fwiw
IF the auto brake adjuster wedge keeps dropping down by itself repeatedly and making brakes too tight again and again time after time - it (the wedge) will need to be deleted for now.
In that case - you have to compensate the brake adjustment on that side - with the adjustment of the eBrake cable on that side.
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I drove it after it had cooled down. I drove it around town at about an average of 35 mph. I didn't seem to be nearly as hot and defiantly wasn't smoking. I'll look into moving the self adjuster asap.
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I finally am on the road again thanks to "Baron VonZeppelin" and is detailed tutorials. I adjusted the self adjuster lever and now everything seems to be great. I think the system needs some adjustment because of sponginess, but is good for now.
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Glad to help the up and coming when possible.
The spongy - more than likely means you need to bleed all 4 wheels again real good. Being sure the brake pedal is not let up on while a bleeder screw is loose.
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alrighty